1. Field of the Invention
The present invention relates to a dual component oral care composition which is effective in the prevention of bacterial plaque accumulation on the teeth as well as in effecting heightened whitening thereof.
2. The Prior Art
Dental plaque is a soft deposit which forms on teeth and is comprised of an accumulation of bacteria and bacterial by-products. Plaque adheres tenaciously at the points of irregularity or discontinuity, e.g., on rough calculus surfaces, at the gum line and the like. Besides being unsightly, plaque is implicated in the occurrence of gingivitis and other forms of periodontal disease.
A wide variety of nonionic antibacterial agents have been suggested in the art to retard plaque formation and the oral infections and dental disease associated with plaque formation. For example, halogenated hydroxydiphenyl ether compounds such as Triclosan are well known to the art for their antibacterial activity and have been used in oral compositions to counter plaque formation by bacterial accumulation in the oral cavity.
Many substances such as tea and coffee that a person confronts or comes in contact with on a daily basis can "stain" or reduce the "whiteness" of one's teeth. Consumers consider clean, white teeth to be aesthetically desirable. Dull-looking, stained teeth are objectionable to most people both on the basis of cosmetic appearance and also socially as an indication of poor oral hygiene. Dental gels containing active oxygen liberating ingredients such as hydrogen peroxide, urea peroxide, percarbonates and perborates of alkali and alkaline earth metals have been disclosed in the prior art for whitening teeth. For example, U.S. Pat. No. 5,766,574 discloses a dual component dental whitening composition which comprises a first gel component containing a peroxide compound and a second paste component containing an abrasive such as silica which is incompatible with the peroxide, the first and second dentifrice components being maintained separate from the other until dispensed and combined for application to teeth requiring whitening.
Although the composition disclosed in U.S. Pat. No. 5,766,574 is effective for whitening, when a noncationic antiplaque agent such as Triclosan was included in the abrasive dentifrice component, it was discovered that when the gel and paste components were combined for application to the teeth, the bioavailability of the Triclosan was inhibited to a level whereby little antiplaque benefit was achieved. Investigation of this problem led to the discovery that polyethylene oxide/polypropylene oxide block copolymers conventionally used as a thickening agents in the preparation of peroxide gels were the factor responsible for the impairment of the antiplaque efficacy of the Triclosan.
Thus, there is a clear need in the art to formulate a dental product capable of delivering both an antiplaque agent such as Triclosan and a peroxide whitening agent during tooth brushing whereby the ingredients used to prepare the dentifrice composition do not inhibit the bioavailability of the antiplaque agent so that optimum antiplaque and whitening benefits result.